-30℃电动汽车补气式CO_(2)热泵制热性能实验研究

Experimental investigation on heating performance of vapor-injection CO_(2) heat pump for electric vehicles at-30℃

为提高极寒环境下电动汽车热泵的供热性能,搭建了二次节流闪发的中间补气式CO_(2)热泵实验台架,并开展了车外-30℃工况下的制热性能研究。实验结果显示,车内进风温度20℃时,无补气系统的排气温度达到176.1℃,通过中间补气排气温度降低了30.7℃,且制冷剂总流量的增加与气冷器侧压力的升高使制热量和COP分别提升了74.1%和43.9%。控制车内进风温度由0℃升高至20℃,补气系统的出风温度从11.9℃升高到32.7℃,但制热量降低了3%,系统能耗增加了43.2%,COP从2.14下降到1.45。随着进风温度的升高,补气热泵循环逐步从亚临界变为跨临界,排气温度和压力均增大,但排气焓值基本不变。

To improve the heating performance of electric vehicle heat pumps in extremely cold environments,an experimental bench of the vapor-injection CO_(2) heat pump with a flash tank was built and the heating performance under the working conditions of-30℃was studied in this paper.The experimental results show that when the inlet air temperature is 20℃,the discharge temperature of the no vapor-injection system reaches 176.1℃,and the discharge temperature is reduced by 30.7℃through the injected refrigerant vapor,and the increase in the total refrigerant flow rate and the pressure of the gas cooler increase the heating capacity and coefficient of performance(COP)by 74.1%and 43.9%,respectively.The inlet air temperature is controlled to increase from 0℃to 20℃,and the outlet air temperature of the vapor-injection system is increased from 11.9℃to 32.7℃,but the heating capacity is reduced by 3%,the energy consumption is increased by 43.2%,and the COP is reduced from 2.14 to 1.45.With the increase of the inlet air temperature,the vapor-injection heat pump cycle gradually changes from subcritical to transcritical,and the discharge temperature and pressure increase,but the discharge enthalpy is unchanged.